Assembly Member for Clwyd West, Darren Millar, said no-one should have to put up with the threat of violence or aggression at work.

"Teachers across Wales do an outstanding job for our young people but need to be supported so they can focus on what they do best - teach," he said.

But a spokesperson for one of Wales's main teaching unions, the UCAC, said the attacks did not just include students.

"We have had increasing reports of our members being attacked by parents, and this is obviously something which needs addressing.

"We are very concerned about the statistics. There are good protection procedures and risk assessments in some local authorities which help reduce the risk and equip teachers with the ability to deal with any violent incidents. But this is not something which is president nationwide."

Leighton Andrews, Welsh Assembly Minister for education and skills confirmed an assault on a member of staff only recorded by the government if it leads to an exclusion from the school. The WG does not collect information on whether a weapon was used in the attacks.

The biggest increases in 2010-11 were:

Swansea - 104 compared to 62 in 2009-10

Caerphilly - 120 exclusions, compared to 83 in 2008-9

Powys - 45 compared to 19 in 2008-9

Newport - 102 compared to 34 in 2007-8

Neath Port Talbot - 90 compared to 36 in 2007-8

Angela Burns, shadow minister for education in Wales, described the figures as "alarming".

"They lay bare the challenges facing teachers in the classroom. Teaching should be one of the most rewarding professions byt the threat of violence can make the job a misery.

"Aggression in the classroom is not only threatening for teachers but also other pupils whose education is interrupted, damaging their prospects."